3.5 Ton 14 SEER 80% AFUE 100,000 BTU Goodman Gas Furnace and Air Conditioner System - Upflow Review 2026

// Bottom Line

This Goodman split system works well for homeowners upgrading from older equipment and wanting reliable performance without premium pricing. The 80% AFUE furnace and variable-speed blower deliver reasonable efficiency, though the 14 SEER rating on the AC side is adequate rather than exceptional by today's standards.

Review

Goodman's 3.5-ton gas furnace and air conditioning system represents the practical middle ground in residential HVAC. The upflow A-coil configuration suits attic or basement installation, while the 100,000 BTU heating capacity and 42,000 BTU cooling output cover typical single-family homes. Energy Star certification signals compliance with federal efficiency standards, making it attractive to environmentally-conscious buyers and those chasing rebates.

The 80% AFUE rating indicates the furnace converts four out of five dollars of gas into usable heat, reasonable for non-condensing equipment but trailing modern 95% AFUE alternatives by $200-400 annually in heating costs. The AC side delivers SEER1 16 performance, outperforming the advertised 14 SEER baseline. Two-stage burner operation and variable-speed blower reduce unnecessary cycling and energy waste compared to single-stage competitors operating at fixed capacity.

Pros & Cons

Pros

Variable-speed blower motor provides better comfort and lower operating costs than single-speed alternatives
Two-stage burner on furnace side enables soft-starts and reduced cycling for improved efficiency
SEER1 rating of 16 exceeds the stated 14 SEER specification, offering better cooling efficiency
Energy Star certified system qualifies for some utility rebates in certain regions
10-year warranty with online registration provides reasonable protection against defects

Cons

80% AFUE furnace efficiency lags modern high-efficiency models which reach 95% AFUE
Spec sheet contains conflicting tonnage information, listing both 3.5 and 5 tons, creating buyer confusion
Single-stage compressor cannot modulate capacity, resulting in on-off cycling rather than variable output

Who Should Buy

Best For

Homeowners in moderate climates replacing 15+ year old systems who prioritize reliability and straightforward installation over cutting-edge efficiency. Contractors serving budget-conscious customers needing a dependable unit that meets Energy Star standards.

Consider Alternatives If

Anyone in extreme climates, those seeking maximum efficiency ratings, or buyers wanting modulating compressor technology should explore higher-tier Goodman or competitor models.

3.5 Ton 14 SEER 80% AFUE 100,000 BTU Goodman Gas F

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Installation

Installation requires standard ductwork compatibility with 2000 CFM maximum airflow. The unit needs 120V single-phase 60Hz power and a 23.5-40 amp breaker, fitting most residential panels without upgrades. Metal exhaust flue and proper refrigerant line sizing, 3/8-inch liquid and 1 1/8-inch suction with 1/2-inch insulation, demand qualified technician work. Footprint of 34.5 inches tall by 21 inches wide suits typical closet spaces.

Warranty & Reliability

Goodman's 10-year parts coverage with online registration protects against manufacturing defects, providing reasonable assurance for system longevity. Registration requirement means keeping documentation accessible. Coverage does not include labor costs, which vary by region but typically run $150-300 per service call. This warranty length is standard across Goodman's mid-range lineup.

Specifications

SKU	LS381183850
Brand/Manufacturer	Online Supply
Cooling BTU	42,000
Heating BTU	100,000
Refrigerant	R410A or R22
Electrical	120 V. 1 Phase 60 Hz
Warranty	10 Years with Online Registration
Decibel Level (dBA)	73
Weight (in lbs)	48.000000
Feature	Spec
Energy Star	Yes
SEER1 (Efficiency)	16
Condenser Stages	Single Stage
Compressor Type	Scroll
Liquid Valve Size	3/8"
Suction Valve Size	7/8"
Max Breaker Size	40 amps
Min. Breaker Size	23.5 amps
Tonnage	5 Ton
Height	34.5"
Width	21"
Depth	28.75"
Resources	Goodman Brochure Goodman Installation Instructions Goodman Parts Manual Goodman Service Manual Goodman Technical Information Goodman User Information Goodman Warranty You will need AdobeÂ® AcrobatÂ® Reader to view PDF documents.
Safety Information	PROPOSITION 65 WARNING This product and many products on our site may contain a chemical know to the state of California to cause cancer or birth defects or other reproductive harm. For more information about Proposition 65 please Click Here.
Configuration	Upflow/Horizontal
Liquid Line	3/8"
Suction Line	1 1/8"
Style	A-Coil
Airflow Direction	Upflow/Horizontal
Exhaust Flue Requirement	Metal
Furnace Efficiency / AFUE	80%
Blower Motor	Variable Speed
Maximum CFM	2000
Burner Stages	Two
Fuel Type	Propane, Natural Gas
Suction Line Insulation Thickness	1/2"
Length	50 feet

Frequently Asked Questions

Why does the spec sheet list both 3.5 and 5 tons? +

The tonnage specification appears contradictory, with the title stating 3.5 tons while specs list 5 tons. Verify actual capacity with your supplier before purchase. This discrepancy needs clarification from the manufacturer or retailer to ensure system sizing matches your home's cooling load calculations.

Can this system use both R410A and R22 refrigerants? +

The specs indicate R410A or R22 compatibility, but this is unusual. Most modern systems use only R410A, as R22 is being phased out. Confirm refrigerant type with your supplier, as this affects parts availability, cost, and future service options over the system's 15-20 year lifespan.

How much will this cost to operate annually? +

At 80% AFUE and 14 SEER with variable-speed blower, expect heating and cooling costs roughly 15-25% higher than high-efficiency 95% AFUE and 18+ SEER systems. Your actual costs depend on climate, home insulation, thermostat use, and local energy rates. Run utility calculations with your supplier.

Is this better than a Lennox or Carrier equivalent? +

Goodman competes on price but trails premium brands in compressor technology and efficiency ratings. Similar-priced Carrier units offer better SEER ratings, while Lennox provides superior customer support. For budget buyers prioritizing reliability over maximum efficiency, Goodman remains solid.

What does the 10-year warranty actually cover? +

Parts defects are covered for 10 years with registration. Labor, refrigerant, routine maintenance, and wear items are excluded. Keep registration proof and purchase documentation. Most manufacturers offer 5-10 year coverage, so this is competitive in Goodman's category.

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